The proposed study is an evaluation of two new methods for increasing the success of the agonist (methadone) to antagonist (naltrexone) transition. Methadone maintained patients have had difficulty starting naltrexone, possibly because of mild withdrawal symptoms during the initial doses of naltrexone. To decrease these symptoms we will use buprenorphine and a combination of clonidine with naltrexone in three studies: 1. An open study is designed to establish the parameters for buprenorphine's use. Patients will be abruptly switched from methadone to buprenorphine and then started on gradually increasing doses of naltrexone. Variations such as tapering the buprenorphine dose or starting with different doses of naltrexone will be tried to optimize symptom reduction. 2. The efficacy of buprenorphine will be compared to methadone tapering for induction onto naltrexone of outpatient methadone maintained patients using a double blind, random assignment trial. 3. We will try to shorten the time for making a transition from methadone maintenance to naltrexone by using both clonidine and buprenorphine. Two sequential randomizations will occur in this double blind trial: 1) at day 0 to clonidine or buprenorphine, 2) at day 17 to naltrexone + clonidine or naltrexone + placebo.